X-ray imaging is a non-invasive technique to capture images of medical patients for clinical diagnosis as well as inspect the contents of sealed containers, such as luggage, packages, and other parcels. To capture these images, an X-ray source irradiates a scan subject with a fan beam of X-rays. The X-rays are then attenuated as the X-rays pass through the scan subject. The degree of attenuation varies across the scan subject because of variances in the internal composition of the subject. The attenuated energy impinges upon an X-ray detector designed to convert the attenuating energy to a form usable in image reconstruction. A control system reads out electrical charge stored in the X-ray detector and generates a corresponding image. For a conventional, screen film detector, the image is developed on a film and displayed using a backlight.
Increasingly, flat panel, digital X-ray detectors are being used to acquire data for image reconstruction. Flat panel detectors are generally constructed as having a scintillator which is used to convert X-rays to visible light that can be detected by a photosensitive layer. The photosensitive layer includes an array of photosensitive or detector elements that each store electrical charge in proportion to the light that is individually detected. Generally, each detector element has a light sensitive region and a region comprised of electronics to control the storage and output of electrical charge. The light sensitive region is typically composed of a photoconductor, and electrons are released in the photoconductor when exposed to visible light. During this exposure, charge is collected in each detector element and is stored in a capacitor situated in the electronics region. After exposure, the charge in each detector element is read out using logic controlled electronics.
In order to maintain optimum image quality, frequent calibration of the digital X-ray detectors and the imaging system (host) is encouraged. However, this requires user intervention, to generate the X-rays at a time when there is nothing “in the beam” in front of the detector. During calibration, the system is not available for use, resulting in loss of productivity of the X-ray system. For digital X-ray detectors that can be used with more than one imaging system the calibration becomes even more complex. To further add to the complexity digital detectors are likely to be wireless and require battery support.
In a typical world of fixed detectors, a system (RAD/RF or Portable) is be calibrated only for one detector or one set of detectors. Also each of the detectors is calibrated with only one system in mind. This is a one to one arrangement.
But with wireless or detachable detectors, the systems primarily support a common interface to attach detectors such as Ethernet/wireless or Ethernet with power combination and the relationship becomes a one to many. That is, a detector can be used with any system that with which the detector can communicate with. If the workflow and design of the systems is similar to the current fixed detector systems (one to one), an operator can try to use a detector that is calibrated for another system, leading to a reduction in the quality of the images and in a reduction in the workflow for that operator. Further, note that the same reduction in workflow is possible when employing multiple mobile systems using wireless detectors. Failures are detected only very late in the workflow and failure will cause significant delay of service to find and use the correct detector for the system.
For the reasons stated above, and for other reasons stated below which will become apparent to those skilled in the art upon reading and understanding the present specification, there is a need in the art for providing an imaging system with access to calibration information for any detector. There is also a need for improved integration of wireless or detachable detectors to an imaging system.